Merge pull request #502 from mulesoft/MULE-7450

MULE-7450 - adding logic in XaTransaction to keep track of the actual Xa...
(cherry picked from commit 5d05476115a9afd6202590d9624df8039c663dd6)

Conflicts:
	modules/db/src/main/jdk6/org/mule/module/db/domain/xa/DataSourceWrapper.java
	modules/db/src/main/jdk7/org/mule/module/db/domain/xa/DataSourceWrapper.java

Merge pull request #505 from mulesoft/MULE-7450

MULE-7450 - XAConnectionFactory is not used as xa resource provider. The...
(cherry picked from commit a3887b0f103211a68c7bda4e8919a5482c2e4128)